Metal material with a bismuth film attached and method for producing same, surface treatment liquid used in said method, and cationic electrodeposition coated metal material and method for producing same

Abstract

This invention provides a metal material with a bismuth coating being enables the subsequent coating to be accomplished at a high throwing power, and has excellent corrosion resistance, coating adhesion, and, being able to be produced with reduced damage to the environment, the metal material having a surface and a bismuth-containing layer deposited on at least a part of the surface of the metal material, wherein a percentage of bismuth atoms in number of atoms in the surface layer of the metal material with a bismuth coating is at least 10%.

1 . A metal material with a bismuth coating comprising a metal material having a surface and a bismuth-containing layer deposited on at least a part of the surface of the metal material, wherein
 a percentage of bismuth atoms in number of atoms in the surface layer of the metal material with a bismuth coating is at least 10%.   
     
     
         2 . The metal material with a bismuth coating according to  claim 1  wherein the metal material has a pocket structure. 
     
     
         3 . The metal material with a bismuth coating according to  claim 1  wherein the bismuth-containing layer is formed in a shape of islands on the surface of the metal material. 
     
     
         4 . A metal material having a coating formed by cationic electrodeposition, comprising the metal material with a bismuth coating of  claim 1 , and the coating formed by cationic electrodeposition on the bismuth coating of the metal material. 
     
     
         5 . A surface treating solution for use in a chemical conversion of a metal material surface conducted as a pretreatment of coating, wherein the surface treating solution contains bismuth and a ligand (L 1 ) for the bismuth. 
     
     
         6 . The surface treating solution according to  claim 5  wherein said coating is cationic electrodeposition. 
     
     
         7 . The surface treating solution according to  claim 5  further comprising a brightener. 
     
     
         8 . The surface treating solution according to  claim 7  wherein the brightener is an organic compound having at least one member selected from the group consisting of aromatic ring, sulfone group, formyl group, carboxy group, and amino group. 
     
     
         9 . The surface treating solution according to  claim 7  wherein the solution at the time of the surface treatment contains the brightener at a weight concentration of 10 to 10,000 ppm. 
     
     
         10 . The surface treating solution according to  claim 5  wherein the ligand (L 1 ) is aminopolycarboxylic acid and/or a carboxylic acid, and the solution contains at least one ligand which has stability for bismuth higher than stability for an ion of a metal constituting the metal material. 
     
     
         11 . The surface treating solution according to  claim 5  wherein
 the ligand (L 1 ) is aminopolycarboxylic acid and/or a carboxylic acid, and has stability for bismuth higher than stability for an ion of a metal constituting the metal material, and 
 the solution further comprises a ligand (L 2 ) which has a stability for the ion of the metal constituting the metal material higher than the stability for bismuth. 
 
     
     
         12 . The surface treating solution according to  claim 5  wherein the solution at the time of the surface treatment contains the bismuth at a weight concentration of 5 to 1,000 ppm. 
     
     
         13 . The surface treating solution according to  claim 12  wherein the solution at the time of the surface treatment contains the ligand at a weight concentration of 5 to 25,000 ppm. 
     
     
         14 . The surface treating solution according to  claim 5  having a pH of at least 2 and less than 10.5. 
     
     
         15 . A method for producing a metal material with a bismuth coating, comprising the step of treating a surface of the metal material with the surface treating solution of  claim 5  to form a bismuth-containing layer on at least a part of the metal material surface. 
     
     
         16 . The method for producing a metal material with a bismuth coating according to  claim 15  wherein the metal material with a bismuth coating comprising a metal material having a surface and a bismuth-containing layer deposited on at least a part of the surface of the metal material, wherein
 a percentage of bismuth atoms in number of atoms in the surface layer of the metal material with a bismuth coating is at least 10%. 
 
     
     
         17 . A method for producing a metal material having a coating formed by cationic electrodeposition, comprising the step of forming a coating by cationic electrodeposition on a surface of the metal material with a bismuth coating produced by the method for producing a metal material with a bismuth coating of  claim 15 . 
     
     
         18 . The surface treating solution according to  claim 7  wherein the ligand (L 1 ) is aminopolycarboxylic acid and/or a carboxylic acid, and the solution contains at least one ligand which has stability for bismuth higher than stability for an ion of a metal constituting the metal material. 
     
     
         19 . The surface treating solution according to  claim 7  wherein
 the ligand (L 1 ) is aminopolycarboxylic acid and/or a carboxylic acid, and has stability for bismuth higher than stability for an ion of a metal constituting the metal material, and 
 the solution further comprises a ligand (L 2 ) which has a stability for the ion of the metal constituting the metal material higher than the stability for bismuth. 
 
     
     
         20 . The surface treating solution according to  claim 7  wherein the solution at the time of the surface treatment contains the bismuth at a weight concentration of 5 to 1,000 ppm. 
     
     
         21 . The surface treating solution according to  claim 7  having a pH of at least 2 and less than 10.5. 
     
     
         22 . A method for producing a metal material with a bismuth coating, comprising the step of treating a surface of the metal material with the surface treating solution of  claim 7  to form a bismuth-containing layer on at least a part of the metal material surface. 
     
     
         23 . A method for producing a metal material having a coating formed by cationic electrodeposition, comprising the step of forming a coating by cationic electrodeposition on a surface of the metal material with a bismuth coating produced by the method for producing a metal material with a bismuth coating of  claim 16 .